The present invention relates to an apparatus for forming a thin film provided with a sputtering target and a vapour source, and a method for producing a thin film using the apparatus.
Formation of a relatively thick (about 1 .mu.m), uniform film of multiple components should be carried out in a short period of time in order to obtain a film of high precision. For example, Japanese Patent Application Laid-open No. 94473/1980 (JP-A-55-94473) discloses an ion-plating apparatus provided with a sputtering target and a vapour source to form a multi-component film.
This apparatus, as shown in FIG. 3, comprises a substrate 46 fixed inside a vacuum chamber 41, a vapour source 45 disposed in the lower part of the vacuum chamber 41, a target 42 and a sputtering electrode 43 each placed between the substrate 46 and the vapour source 45, an anode 44 disposed on the side of the vapour source 45, and a hot cathode 47 provided on the side of the substrate 46 to generate gas-discharge plasma. In the vacuum chamber 41 of this apparatus, where gas is introduced from a gas supply source 48, a film is formed by evaporating the vapour source 45 at a constant rate through heating and then ionising the particles of the evaporated components in gas-discharge plasma, as well as applying a high-frequency magnetic field to the sputtering electrode 43 for sputtering the target 42. The film formed on the substrate 46 is composed of the evaporated component and the sputtered component.
This ion-plating apparatus, however, fails to produce a uniform film on a large substrate, which is in great demand recently. In the vacuum chamber 41, while the vapour source 45 faces the substrate 46, the target 42 is arranged approximately perpendicular to the substrate 46 in the vicinity thereof. This structure prevents particles sputtered out of the target 42 from uniformly reaching the surface of a large substrate to give a uniform layer.
Besides, the substrate 46 and the vapour source 45 are spaced at such a distance that the ionised evaporated particles cannot reach the substrate in a short time. This causes degradation of the precision of a film.